多级离心泵水力性能数值预测涡量分析法

为了研究利用CFD技术预测多级离心泵水力性能的方法,选取某一多级离心泵为研究对象.采用数值模拟方法获得了多级离心泵内部全流场信息.分别选取多级离心泵单级、二级、三级的三维模型进行全流场数值模拟,获得了3种三维模型各水力部件内部的的水力损失,通过对计算结果分析发现,多级离心泵内部各级水力损失大小基本类似,不随级数的不同而改变,这为通过对少级数的数值模拟以预测更多级数的泵性能提供了依据.通过对多级离心泵内部流场各级能量损失进行分析,分析各级能量损失特征及其流动特点,发现各级涡量分布基本一致,损失特性相同,只在最后一级导叶内部的涡结构有一定的区别.采用能量分析结合多级泵内部流场涡动力学分析方法建立了多级离心泵性能数值预测的计算方法,并建立了多级离心泵性能预测基于少级数模型数值分析的计算公式.

Numerical prediction of multistage centrifugal pump performance and analysis of vorticity of flow field

In order to develop a CFD-based method for predicting hydraulic performance of multistage centrifugal pump, a multistage centrifugal pump is selected as the study object, and the information of flow field in the whole pump is obtained as well. Specially, the three-dimensional flow domain models of single-, two- and three-stage for the pump are generated and the hydraulic loss across each through-flow component in every stage in those models is obtained. It is shown that the hydraulic loss across a through-flow component in the single-stage model is basically similar to that across the counterpart in the two- or three-stage model, implying the loss is independent of the number of stages chosen and a model with less number of stages can be used to predict performance of a multistage centrifugal pump. By analyzing the energy loss in the models of multistage centrifugal pump to demonstrate the loss characteristics and flow features in each stage, it is found that the vortex structure is nearly consistent across every stage except the diffuser in the last stage. By making use of energy analysis combined with vortex dynamics approach, a set of formulas for predicting the performance of multistage centrifugal pump are established according to a computational model with a few stages. 